36E77619B0014-0005002.pdf

WATER | ENERGY & RESOURCES | ENVIRONMENT | PROPERTY & BUILDINGS | TRANSPORTATION

GHD Geotechnical Investigation

SFVAMC - PICU Expansion and Renovation San Francisco, California

November 2015

GHD Inc 4080 Plaza Goldorado Circle Suite B Cameron Park CA 95682 USA T 1 530 677 5515 W www.ghd.com

November 5, 2015

Paige Smith

POLYTECH ASSOCIATES INC.

235 Pine Street, 17th Floor San Francisco, CA 94104

RE: Geotechnical Investigation, SFVAMC - PICU Expansion and Renovation

Dear Ms. Smith, GHD Inc (GHD) is pleased to present the attached report containing the results of our geotechnical investigation for the proposed San Francisco VA Medical Center (SFVAMC) - Psychiatric Intensive Care Unit (PICU) Expansion and Renovation project in San Francisco, California. It is our understanding that Building 203 will be expanded and renovated. The southwest corner of the “A” wing of the building will be expanded to the south with 1,100 square feet of new PICU space. The western portion (8,000 square feet) of the “A” wing of the existing PICU facility will be renovated. It is our understanding that structural improvements are not required for the renovation portion and therefore geotechnical input is not needed.

The accompanying report presents our findings, conclusions, and recommendations developed from our geotechnical investigation. Contained in the report are geotechnical design criteria and recommendations for design and construction of the proposed building addition as well as earthwork recommendations. The results of the subsurface exploration and laboratory testing programs, which form the basis of our recommendations, are also included in the report. On the basis of our investigation, the site is suitable, from a geotechnical perspective, to receive the planned improvements provided the recommendations included in the report are incorporated into the design and construction of the project.

If you have any questions regarding the information contained in this report, or if we may be of further assistance, please do not hesitate to contact us.

Sincerely, GHD Inc

Christopher D. Trumbull, P.E., G.E., D.GE Kyle Jermstad, E.I.T.

Senior Geotechnical Engineer Staff Engineer

Project No. 11109034 ii November 2015 Geotechnical Investigation

Contents

1. Introduction

1.1 Project Description

1.2 Purpose and Scope of Work

2. Field Exploration and Laboratory Testing

2.1 Field Exploration

2.2 Laboratory Testing

3. Site and Subsurface Conditions

3.1 Site Conditions

3.2 Subsurface Conditions

3.2.1 General Geology and Faulting

3.2.2 Subsurface Materials

3.2.3 Groundwater Conditions

4. Conclusions

4.1 Foundation Support and Settlement

4.2 Expansion Potential

4.3 Slope Stability

4.4 Groundwater and Wet Weather Earthwork

4.5 Ground Shaking

4.5.1 Liquefaction

4.6 Corrosion

5. Recommendations

5.1 Site Preparation and Earthwork

5.1.1 Site Preparation

5.1.2 Earthwork

5.1.3 Temporary Slopes/Shoring

5.2 Foundations – Helical Piles

5.3 Seismic Design

5.4 Surface Drainage and Erosion Control

Project No. 11109034 iii November 2015 Geotechnical Investigation

5.5 Plan Review and Construction Observation

6. References

7. Limitations

Table Index Table 1 Soil Corrosion Results Table 2 10-Point Soil Corrosion Evaluation System Table 3 Import Fill Specifications Table 4 Helical Pile Capacities Table 5 Seismic Design Criteria

Appendices

A Figures B Logs of Borings C Laboratory Test Results

Project No. 11109034 iv November 2015 Geotechnical Investigation

Distribution

To: Paige Smith

CC: Rich Graziano

POLYTECH ASSOCIATES INC.

235 Pine Street, 17th Floor

San Francisco, CA 94104

From: GHD Inc

Christopher Trumbull, P.E., G.E., D.GE

Kyle M. Jermstad, E.I.T., Q.S.P.

4080 Plaza Goldorado Circle, Suite B

Cameron Park, CA 95682

Project No. 11109034 1 November 2015 Geotechnical Investigation

1. Introduction

This report presents the findings, conclusions, and recommendations developed from our geotechnical investigation. The investigation was conducted in accordance with the Standard Form of Agreement Between Architect and Consultant signed July 2, 2015.

1.1 Project Description

It is our understanding that Building 203 will be expanded and renovated. The southwest corner of the “A” wing of the building will be expanded to the south with 1,100 square feet of new PICU space. The western portion (8,000 square feet) of the “A” wing of the existing PICU facility will be renovated. We understand individual column loads are 160 kips (120 kips dead load and 40 kips live load), according to Mr. Robert Graff of Degenkolb Engineers. There are no uplift or lateral loads, as they are being applied to the existing structure. It is also our understanding that structural improvements of the existing building are not required and therefore geotechnical input is not needed.

1.2 Purpose and Scope of Work

The purpose of this investigation was to evaluate the suitability of the project site, from a geotechnical perspective, for the proposed improvements. The main objectives of the investigation were to characterize the subsurface materials, perform engineering analyses, develop geotechnical recommendations and criteria to be used for design and construction, and document our findings, conclusions, and recommendations in this report.

The scope of our geotechnical investigation included the following:

• A review of published geologic and geotechnical material pertaining to the site vicinity;

• One boring drilled to an approximate depth of 41½ feet to obtain sufficient information to evaluate the subsurface conditions and provide foundation recommendations for the expansion;

• Performing geotechnical laboratory testing on select soil samples collected from the borings;

• Engineering analyses to develop geotechnical design criteria and recommendations for the proposed project; and

• Preparation of this report.

Project No. 11109034 2 November 2015 Geotechnical Investigation

2. Field Exploration and Laboratory Testing

2.1 Field Exploration

One boring was drilled to an approximate depth of 41½ feet below ground surface (bgs) on August 14, 2015 at the approximate location shown in Figures A-1 and A-2. The boring was located in the field based on a land survey by others. The boring was drilled under the supervision of Kyle Jermstad of GHD utilizing a truck-mounted CME-55 drill rig equipped with 6-inch solid flight augers. Samples were collected using both Modified California and SPT samplers driven by an automatic hammer with a weight of 140 pounds and a drop of 30 inches.

The number of blows required for each 6-inch increment of drive were recorded and the cumulative blow count for the 12 inches of drive (following the first 6 inches of “seating” drive), or fraction thereof where resistance was encountered, is presented in the logs of borings. The blow counts presented in the logs are uncorrected and shown as they were recorded in the field. Both the samples and drill cuttings were visually classified in the field based on the Unified Soil Classification System (USCS) in general accordance with ASTM D2488.

The subsurface conditions encountered are summarized in Section 3.2. Logs of the borings were initially prepared based on the field logging and visual examination of the soil samples in the field. Considering the results of the laboratory testing, the soil classifications were finalized in general accordance with

ASTM D2478.

The soil boring key and the logs of borings are presented in Appendix B.

Previous explorations by others performed in the project area include the following:

• Eight borings drilled by Woodward-Lundgren & Associates in 1971 to a maximum depth of 43 feet below ground surface; and

• One boring performed by Fugro in 2011 to a maximum depth of 45.4 feet below ground surface.

The soil boring key, logs of borings, and laboratory results performed by others are presented in Appendix D.

2.2 Laboratory Testing

Laboratory testing was conducted on disturbed soil samples recovered during the site investigation.

Tests conducted include the following:

• Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil, Rock by Mass (ASTM D2216);

• Standard Test Method for Liquid Limit, Plastic Limit, and Plasticity Index of Soils (ASTM D4318);

• Standard Test Method for Particle-Size Analysis of Soils (ASTM D422);

• Method of Testing Soil and Waters for Sulfate Content (CTM 417);

Project No. 11109034 3 November 2015 Geotechnical Investigation

• Method of Testing Soil and Waters for Chloride Content (CTM 422);

• Method for Estimating the Service Life of Steel Culverts (CTM 643);

• Redox Potential ASTM D1498m; and

• Sulfides (AWWA C105/A25.5)

Geotechnical laboratory test results are presented in Appendix C.

Project No. 11109034 4 November 2015 Geotechnical Investigation

3. Site and Subsurface Conditions

3.1 Site Conditions

The site is located at the VA Medical Center at the northwest corner of the San Francisco Peninsula. The proposed addition is located at the southwest corner of the A-wing of Building 203, the Psychiatric Intensive Care Unit. At the time of our exploration the flat site was occupied by an at-grade concrete loading dock and air conditioning units.

3.2 Subsurface Conditions

3.2.1 General Geology and Faulting

The area is mapped as being primarily composed of Quaternary dune sand (Qs) overlying Franciscan Complex. The nearest active fault to the site is the San Andreas Fault, which is just less than 4½ miles to the west. The San Andreas Fault is an active dextral strike-slip fault with Holocene and Historic movement. According to the Alquist-Priolo Earthquake Fault Zone Act, the surrounding project area is not within a Special Studies Zone; however, the property is bordered by a California Geological Survey Earthquake Induced Landslide Study Zone. Strong ground shaking at the site should be expected during an earthquake.

3.2.2 Subsurface Materials

Six inches of concrete existed at the ground surface. The results of our field exploration and laboratory analyses indicate the subsurface materials below the concrete generally consist of medium dense SAND (SP) to an approximate depth of 22½ feet. Medium dense to dense clayey SAND (SC) was encountered at an approximate depth of 22½ feet to 38 feet. Franciscan Formation was encountered below the sand to the maximum depth explored, approximately 41½ feet bgs. The subsurface conditions are in general agreement with the materials presented on boring logs by others in the close proximity. Details of subsurface materials are presented in the GHD logs of borings as well as previous borings by others presented in Appendix B.

3.2.3 Groundwater Conditions

The depth to groundwater was measured by GHD at 30½ feet bgs at the time of drilling in the recent boring. Although free groundwater was not noted by Fugro in its 2011 Boring B-1, seepage was noted at 21 feet. It should be noted that the borings may not have been left open long enough to establish equilibrium groundwater conditions. In addition, fluctuations in groundwater level could occur due to changes in season, variations in rainfall, pumping, or other factors.

Project No. 11109034 5 November 2015 Geotechnical Investigation

4. Conclusions

The site is suitable for the proposed improvements provided the recommendations presented herein are incorporated into the design and construction of the project.

4.1 Foundation Support and Settlement

Based on our subsurface exploration, the sandy bearing materials are moderately strong and are not questionable. The proposed addition foundation can be supported on a deep foundation deriving support from the native sandy soil. For foundations and subgrade designed and prepared as recommended in this report, differential settlements are expected to be no greater than 1/2 inch over a horizontal distance of 50 feet. Total settlements of less than ½ inch are anticipated.

4.2 Expansion Potential

Expansive soils are defined as soils that undergo large volume changes (shrink or swell) due to variations in moisture content and meet four provisions in the 2012 International Building Code (IBC). Such volume changes may cause damaging settlement and/or heave of foundations, slabs-on-grade, pavements, etc.

The sandy soil encountered does not meet the IBC provisions and has a low expansion potential.

4.3 Slope Stability

Landslides occur due to multiple factors, including slope inclination, bedrock geology, geologic structure, geomorphology, weathering, vegetation, and precipitation. Due to the relatively flat inclination of the site, landslide potential is considered negligible.

4.4 Groundwater and Wet Weather Earthwork

Groundwater was encountered at 30½ feet bgs during GHD’s recent drilling and is not anticipated to be encountered during construction. At the time of our field exploration, the existing near surface soils were dry to moist. These soils could become unworkable during and shortly after periods of rainfall and require drying to reach a workable moisture content.

4.5 Ground Shaking

The site vicinity is located in an area generally characterized as having high seismicity. Using the USGS Seismic Hazard Tool Website considering the site location, ASCE7-10/NEHRP, and Type D soils, the Peak Ground Acceleration (PGA) is 0.77g. Strong ground shaking at the site should be expected during an earthquake.

Project No. 11109034 6 November 2015 Geotechnical Investigation

4.5.1 Liquefaction

Liquefaction occurs when excess pore pressures are generated in loose, saturated, generally cohesionless soil (sand, gravel, and some silts) during earthquake shaking, causing the soil to experience a partial to complete loss of shear strength. Such a loss of shear strength can result in settlement and/or horizontal movement (lateral spreading) of the soil mass.

One boring was drilled to a depth of 41½ feet at the proposed expansion site to characterize the subsurface materials regarding liquefaction. We performed a liquefaction analysis of each boring in following guidance from Boulanger and Idriss, 2004, using the LiqIT v 4.7 software. Nearby borings by others were considered as well.

For the project site, the PGA expected is 0.77g (ASCE 7-10, Type D soil) and a design moment magnitude from the San Andreas Fault of 7.9. The seismic information, sample depth, blow count, estimated unit weight, fines contents, soil types, and groundwater depth were entered into software. For the soil layers that were susceptible to liquefaction, the liquefaction induced settlement was estimated using the procedures by Ishihara and Yoshimine (1992). Procedures by Iwasaki et al (1978) were used to estimate the probability of liquefaction.

The results of the liquefaction analysis indicate factors of safety against liquefaction above two for all soil layers. Based on the procedures by Iwasaki, the potential for liquefaction is zero. In addition, based on the Seismic Hazards Zones, City and County of San Francisco (California Division of Mines and Geology, 2000), the site is not in a location zoned with historical liquefaction; therefore, the potential for ground settlement due to liquefaction is low.

4.6 Corrosion

Soils corrosivity analysis is important for estimating and mitigating the deterioration of buried ferrous metals and concrete. We performed corrosion testing on a representative sample from boring B-1 at a depth of 2 feet bgs as an indicator of the corrosive properties of the soil. Test results are summarized below in Table 1 and presented in detail in Appendix C.

Table 1 Soil Corrosion Results

Boring No.

Depth (ft.) pH

Minimum Resistivity (ohm-cm)

Water Soluble Sulfates (ppm)

Water Soluble

Chlorides (ppm)

Redox Potential

(mV)

Points

B-1 2 8.89 5,360 23.6 8.0 179.00 3

Project No. 11109034 7 November 2015 Geotechnical Investigation

According to ACI 318, a sulfate concentration less than 1,000 parts per million is considered “not applicable” (i.e., no mitigation required). A water soluble chloride content of less than 500 ppm is generally non-corrosive to reinforced concrete.

To evaluate the potential for external corrosion potential on ductile iron pipe from soil, the 10-point system in C105/A21.5 (ANSI/AWWA, 1999) was used. As shown in Table 1 above, a point value based on the values in Table 2 below. The long life of historical unprotected pipe in soil with less than 10 points indicates a non-corrosive environment (AWWA 2005).

The provided preliminary corrosion test results are only an indicator of potential soil corrosivity for the sample tested at the selected depth interval. It is possible that corrosion potential can vary by sample location and depth.

Our scope of services does not include corrosion engineering; therefore, a detailed analysis of the corrosion test results is not included in this report. A qualified corrosion engineer should be retained to review the test results and design any mitigation that may be required.

Project No. 11109034 8 November 2015 Geotechnical Investigation

Table 2 10-Point Soil Corrosion Evaluation System

Project No. 11109034 9 November 2015 Geotechnical Investigation

5. Recommendations

5.1 Site Preparation and Earthwork

5.1.1 Site Preparation

General site preparation should include the stripping of any surface vegetation including the root zone.

Existing utilities less than 5 feet below foundations should be evaluated by GHD geotechnical staff in the field on a case-by-case basis.

5.1.2 Earthwork

5.1.2.1 General Subgrade Preparation

Any soft or loose areas should be stabilized. Stabilization may be accomplished by excavating to firm, native material and replacing with engineered fill or using woven geosynthetics or geogrids. Proof-rolling and final verification of stabilization should be conducted under the observation of a GHD geotechnical representative. Upon completion of subgrade preparation, engineered fill should be placed as described below.

5.1.2.2 Engineered Fill

Engineered fill should consist of a homogenous mixture of soil and rock free of vegetation, organic material, and rubble. Highly plastic or organic soils should not be used for engineered fill but may be placed in landscape areas.

We anticipate that the materials generated from on-site excavations will be suitable for use as engineered fill. Imported material to be used as engineered fill should meet the specifications listed below in Table 3 after compaction.

Table 3 Import Fill Specifications

GHD geotechnical staff should observe and approve import fill material in writing prior to the material being brought on site. Engineered fill material should not contain rocks greater than 6 inches in largest dimension. Rocks placed in fill should be surrounded by a well-compacted soil matrix to prevent “nesting” and the creation of voids within the fill.

Direct Shear

(ASTM D3080)

Atterberg Limits

(ASTM D4318)

Particle Size

(ASTM C136 or D422)

30˚ PI < 15

LL < 40

100% passing the 6 inch sieve minimum of 85% passing the 2-1/2 inch sieve maximum of 30% passing the #200 sieve

Project No. 11109034 10 November 2015 Geotechnical Investigation

5.1.2.3 Compaction

Engineered fill should be moisture conditioned as necessary, placed in horizontal loose lifts not exceeding 8 inches in thickness, and compacted to a minimum of 90 percent of the maximum dry density as determined by ASTM D1557 for fills less than 5 feet in thickness. In areas to receive paved improvements, or fills thicker than 5 feet, fill should be compacted to 95 percent of ASTM D1557.

Placement of fill material should be verified by a GHD geotechnical representative on a continuous basis.

5.1.2.4 Trench Backfill

Trench backfill should meet the Engineered Fill specifications detailed above. Trench backfill should be placed in lifts not exceeding 12 inches in thickness and compacted to 90 percent of ASTM D1557 by mechanical means only (no jetting). In areas to receive paved improvements, 95 percent of ASTM D1557 is required. Pipe bedding shall conform to the pipe manufacturer’s recommendations.

5.1.3 Temporary Slopes/Shoring

Temporary slopes and shoring should conform to OSHA standards. Shored excavations should be constructed from the top down in cuts not exceeding 5 vertical feet in depth. Excavation of subsequent cuts should not be performed until shoring of the adjacent upper cut has been completed. Protection of workers and adjacent structures, shoring design, and the stability of all temporary slopes should be contractually established as solely the responsibility of the contractor.

Foundation excavations for new structures may be near existing foundations. In order to minimize impacts on the existing facilities during excavation, GHD recommends that trenching be located outside an imaginary 1.5:1 (H:V) plane from the base of the existing foundation in firm native undisturbed soil. In the event that this recommendation is not practical, the designer shall incorporate trench shoring or structural improvements such as sheet piling to protect the existing adjacent foundations. Trench support shall be designed by a Professional Engineer registered in the State of California and shall consider adjacent surcharge.

5.2 Foundations – Helical Piles

It is our understanding that Building 203 is supported on deep foundations. In order to maintain a similar settlement potential, we recommend the expansion be supported by a deep foundation as well. Provided within this section are recommendations for bearing capacity of helical pile deep foundations. The bearing stratum consists of dense sand and the top helix should be at least 15 feet below the existing slab. The piles should have a round shaft with a wall thickness of at least 0.30 inches. Helical piles should be manufactured by Chance Civil Construction or equivalent.

Select configurations and capacities are presented below in Table 4.

Project No. 11109034 11 November 2015 Geotechnical Investigation

Table 4 Helical Pile Capacities

Individual Helix

Configuration

Shaft Diameter

(in) Depth to Top

Helix (ft) Allowable Vertical

Capacity (kips)

Installation Torque

Range (ft-lbs)

10/12/14/14 3.5 15 82 10,000

12/14/14/14 3.5 15 88 10,000

To avoid a capacity reduction due to group effects, individual piles should be spaced at least three times the diameter of the largest helix, or a minimum of 42 inches for the configurations above. If closer pile spacing is necessary, GHD should be contacted for appropriate group reduction values.

The installation torque of each pile should be monitored and recorded during installation by a GHD geotechnical representative to confirm the minimum torque to achieve design capacity is reached and that the maximum torque rating is not exceeded. The helical piles should be designed and installed in accordance with the manufacturer’s specifications and recommendations. Load testing should be performed on each helical pile to confirm that design loadings are supported.

Total settlement should be less than ½ inch and differential settlement across the structure should be less than ½ inch.

5.3 Seismic Design

The seismic design criteria for the site (37.78162°N, 122.50579°W), listed in the table below, were developed in accordance with ASCE 7-10 and 2009 NEHRP based on the subsurface information obtained from our geotechnical investigation.

Table 5 Seismic Design Criteria

Parameter Recommended Value

Reference

(ASCE/SEI 7-10)

Site Class D Table 20.3-1

Mapped MCE spectral response at short period (SS) 1.955 g Figure 22-1

Mapped MCE spectral response at 1 sec period (S1) 0.917 g Figure 22-2

Site coefficient (Fa) 1.0 Table 11.4-1

Site coefficient (Fv) 1.5 Table 11.4-2

MCE spectral response acceleration for short period (SMS) 1.955 g Equation 11.4-1

MCE spectral response acceleration for 1 sec period (SM1) 1.375 g Equation 11.4-2

Design Spectral Acceleration for short period (SDS) 1.303 g Equation 11.4-3

Design Spectral Acceleration for 1 sec period (SD1) 0.917 g Equation 11.4-4

Project No. 11109034 12 November 2015 Geotechnical Investigation

5.4 Surface Drainage and Erosion Control

Drainage around the receiving structure should be constructed in a way such that soils near the foundation do not become saturated. Surfaces within 10 feet of structures should be sloped a minimum of 2 percent to direct water away and prevent ponding. We recommend the surface drainage be designed in accordance with the latest edition of the IBC.

Erosion control measures should be implemented for exposed surfaces, which may be subject to soil erosion during periods of intensive rainfall. In general, all construction surfaces should be graded to drain to prevent water from ponding.

5.5 Plan Review and Construction Observation

Our conclusions and recommendations are contingent upon GHD being retained to review project plans and specifications during the construction document phase to evaluate if they are consistent with our recommendations. They are also contingent upon GHD being retained to provide intermittent observation and appropriate field and laboratory testing during site preparation and grading, excavation, helical pile installation, and fill placement and compaction to evaluate if the subsurface conditions are as anticipated.

If the subsurface conditions are observed to be different from those described in this report, we should be notified immediately so that the changed conditions can be evaluated and our recommendations revised, if appropriate. The recommendations in this report are contingent upon our notification and review of changed conditions. These services are performed on an as-requested basis and are in addition to this geotechnical investigation. We cannot provide comment on conditions, situations, or stages of construction that we are not notified to observe.

Project No. 11109034 13 November 2015 Geotechnical Investigation

6. References

Idriss, I. M., and Boulanger, R. W., Soil Liquefaction During Earthquakes.” Monograph MNO-12, Iwasaki T, Tokida K, Tatsuko F, Yasuda S (1978), A Practical Method For Assessing Soil Liquefaction Potential Based On Case Studies At Various Sites In Japan, Proc. 2nd. Int. Conf. on Microzonation, San Francisco, Vol.2.Earthquake Engineering Research Institute, Oakland, CA, 2008.

Ishihara, K., and Yoshimine, M., 1992. Evaluation of settlements in sand deposits following liquefaction during earthquakes, Soils and Foundations 32(1), 173–88.

California Division of Mines and Geology (2000), Seismic Hazards Zones, City and County of San Francisco, California Department of Transportation (Caltrans). 2003. Corrosion Guidelines.

Boulanger and Idriss, 2004, Evaluating the Potential For Liquefaction Or Cyclic Failure Of Silts And Clays

U.S. Geologic Survey, June 12, 2014, U.S. Seismic Design Maps, http://earthquake.usgs.gov/designmaps/us/application.php.

Chance Civil Construction, Design, Installation and Testing of Helical Piles & Anchors

USGS Scientific Investigations Map 2918, Geologic Map of San Francisco County, CA .KMZ

INTERNATIONAL CODE COUNCIL, INC. May 30, 2014, 2015 International Building Code http://earthquake.usgs.gov/designmaps/us/application.php

Project No. 11109034 14 November 2015 Geotechnical Investigation

7. Limitations

This Geotechnical Investigation (“Report”):

• Has been prepared by GHD Inc (“GHD”) for POLYTECH ASSOCIATES INC. under the professional supervision of those senior partners and/or senior staff whose seals and signatures appear herein.

• May only be used and relied on by POLYTECH ASSOCIATES INC., which is responsible to ensure that all relevant parties to the project, including designers, contractors, subcontractors, etc., are made aware of this report in its entirety.

• Must not be copied to, used by, or relied on by any person other than POLYTECH ASSOCIATES INC. without the prior written consent of GHD; and

• May only be used for the purpose of engineering design of the proposed structures at the project site described in this report (and must not be used for any other purpose).

GHD and its servants, employees and officers otherwise expressly disclaim responsibility to any person other than POLYTECH ASSOCIATES INC. arising from or in connection with this Report.

To the maximum extent permitted by law, all implied warranties and conditions in relation to the services provided by GHD and the Report are excluded unless they are expressly stated to apply in this Report.

The services undertaken by GHD in connection with preparing this Report:

• In regard to site exploration and testing o Site exploration and testing characterizes subsurface conditions only at the locations where the explorations or tests are performed; actual subsurface conditions between explorations may be different than those described in this report. Variations of subsurface conditions from those analyzed or characterized in this report are not uncommon and may become evident during construction. In addition, changes in the condition of the site can occur over time as a result of either natural processes (such as earthquakes, flooding, or changes in ground water levels) or human activity (such as construction adjacent to the site, dumping of fill, or excavating). If changes to the site’s surface or subsurface conditions occur since the performance of the field work described in this report, or if differing subsurface conditions are encountered, we should be contacted immediately to evaluate the differing conditions to assess if the opinions, conclusions, and recommendations provided in this report are still applicable or should be amended.

• In regard to limitations o Our scope of services was limited to the proposed work described in this report, and did not address other items or areas.

o The geotechnical investigation upon which this report is based was conducted for the proposed structures at the project site described in this report. The conclusions and recommendations contained in this report are not valid for other structures and/or project sites. If the proposed project is modified or relocated, or if the subsurface conditions found during construction differ from those described in this report, GHD should be

Project No. 11109034 15 November 2015 Geotechnical Investigation provided the opportunity to review the new information or changed conditions to determine if our conclusions and recommendations need revision.

• Did not include evaluation or investigation of the presence or absence of wetlands.

• Did not include a fault investigation.

GHD expressly disclaims responsibility for any error in, or omission from, this Report arising from or in connection with any of the Assumptions being incorrect. There is no warranty, either expressed or implied. GHD accepts no liability regarding completeness or accuracy of the information presented and/or provided to us, or any conclusions and decisions which may be made by the client or others regarding the subject site/project. Verification of our conclusions and recommendations is subject to our review of the project plans and specifications, and our observations of construction.

Subject to the paragraphs in this section of the Report, the interpretations of data, findings, conclusions, recommendations and professional opinions in this Report are based on the information reviewed, site conditions encountered, and samples collected during our field exploration and were developed in accordance with generally accepted geotechnical engineering principles and practices and as prescribed by the client. This Report is considered valid for the proposed project for a period of two years from the report date provided that the site conditions and development plans remain unchanged. With the passage of time, changes in the conditions of a property can occur due to natural processes or the works of man on this or adjacent properties. Legislation or the broadening of knowledge may result in changes in applicable standards. Depending on the magnitude of any changes, GHD may require that additional studies (at additional cost) be performed and that an updated report be issued. Additional studies may disclose information which may significantly modify the findings of this report. GHD will retain untested samples collected during our field investigation for a period not to exceed 60 days unless other arrangements are made with the client. After a period of two years from the report date, GHD expressly disclaims responsibility for any error in, or omission from, this Report arising from or in connection with those opinions, conclusions and any recommendations.

Project No. 11109034 A November 2015 Geotechnical Investigation

Appendix A

Figures

PROJECT

LOCATION

N

SCALE: 1"=600'

Vicinity Map

SFVAMC - PICU Expansion & Renovation

San Francisco, CA

Project Number: 11109034

A-1

FIGURE

B-1

N

0 80'40'

1"=40'

LEGEND

Approximate Location of Boring by GHD

WLA W1-71

FUGRO B-1

WLA WF-62

Approximate Location of Boring by Woodward Lungren & Assoc.

Boring Location Map

SFVAMC - PICU Expansion & Renovation

San Francisco, CA

Project Number: 11109034

A-2

FIGURE

WLA W2-71

WLA W5-71

WLA W4-71

WLA W8-71

Approximate Location of Boring by FUGRO

Project No. 11109034 B November 2015 Geotechnical Investigation

Appendix B

Logs of Borings

VA Medical Center San Francisco-PICU Expansion & Renovation San Francisco, CA

Project Number: 11109034

BOULDERS

COBBLES

GRAVEL: COARSE

GRAVEL: FINE

SAND: COARSE

SAND: MEDIUM

SAND: FINE

SILT

CLAY

WELL GRADED - HAVING WIDE RANGE OF GRAIN SIZES AND APPRECIABLE

AMOUNTS OF ALL INTERMEDIATE PARTICLE SIZES

SYMBOLS

SANDS

WITH FINES

WELL-GRADED GRAVELS,

GRAVEL - SAND MIXTURES,

LITTLE OR NO FINES

INORGANIC CLAYS OF LOW TO

MEDIUM PLASTICITY, GRAVELLY

CLAYS, SANDY CLAYS, SILTY CLAYS,

LEAN CLAYS

COARSE

GRAINED

SOIL

PARTICLE SIZE IDENTIFICATION

SAMPLE SYMBOLS

GENERAL NOTES

WELL SYMBOLS WATER LEVEL SYMBOLS

Water level measured at a specified time after drilling and sampling or well completion.

Water level at time of drilling.

POORLY GRADED - PREDOMINATELY ONE GRAIN SIZE, OR HAVING A RANGE OF

SIZES WITH SOME INTERMEDIATE SIZES MISSING

MORE THAN

50% OF

MATERIAL IS

SMALLER

THAN NO. 200

SIEVE SIZE

APPRECIABLE

AMOUNT OF

FINES

LITTLE OR NO

FINES

APPRECIABLE

AMOUNT OF

FINES

LITTLE OR NO

FINES

GW

GP

GM

GC

SW

SP

SM

SC

ML

CL

OL

MH

CH

OH

PT

CLEAN

SANDS

GRAVELS

WITH FINES

CLEAN

GRAVELS

LIQUID LIMIT

GREATER

THAN 50

MORE THAN

50% OF

MATERIAL IS

LARGER THAN

NO. 200 SIEVE

SIZE

1. Soil classifications are based on the Unified Soil Classification System. Soil descriptions and stratum lines are interpretive, and actual changes may be gradual. Field descriptions may have been modified to reflect results of laboratory tests.

2. Descriptions on these logs apply only at the specific boring locations and at the time the borings were advanced. They are not warranted to be representative of subsurface conditions at other locations.

3. Abbreviations:

CD = TX-CD

CN = Consolidation CR = Corrosivity

CU = TX-CU

DS = Direct Shear EI = Expansion Index

NR = No Recovery PR = Permeability RV = R-Value TC = Cyclic Triaxial UC = Unconfined Compression UU = TX-UU (quick) Z = Ziplock

NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS

SILTS

AND

CLAYS

LIQUID LIMIT

LESS THAN 50

POORLY-GRADED GRAVELS,

GRAVEL - SAND MIXTURES,

LITTLE OR NO FINES

UNIFIED SOIL CLASSIFICATION AND SYMBOL CHART

DESCRIPTIONS

MORE THAN

50% OF

COARSE

FRACTION

RETAINED ON

NO. 4 SIEVE

MORE THAN

50% OF

COARSE

FRACTION

PASSING ON

NO. 4 SIEVE

SILTS

AND

CLAYS

FINE

GRAINED

SOIL

CLAYEY GRAVELS, GRAVEL -

SAND - CLAY MIXTURES

WELL-GRADED SANDS,

GRAVELLY SANDS, LITTLE OR

NO FINES

POORLY-GRADED SANDS,

GRAVELLY SAND, LITTLE OR NO

FINES

SAND AND

SANDY SOIL

HIGHLY ORGANIC SOIL

SILTY SANDS, SAND - SILT

MIXTURES

CLAYEY SANDS, SAND - CLAY

MIXTURES

ORGANIC SILTS AND ORGANIC

SILTY CLAYS OF LOW

PLASTICITY

INORGANIC SILTS, MICACEOUS

OR DIATOMACEOUS FINE SAND

OR SILTY SOILS

PEAT, HUMUS, SWAMP SOILS

WITH HIGH ORGANIC

CONTENTS

INORGANIC CLAYS OF HIGH

PLASTICITY

MAJOR DIVISIONS

INORGANIC SILTS AND VERY FINE SANDS,

ROCK FLOUR, SILTY OR CLAYEY FINE

SANDS OR CLAYEY SILTS WITH SLIGHT

PLASTICITY

ORGANIC CLAYS OF MEDIUM TO

HIGH PLASTICITY, ORGANIC SILTS

SILTY GRAVELS, GRAVEL - SAND -

SILT MIXTURES

>12 in 3 - 12 in 3/4 - 3 in

No.4 - 3/4 in No.10 - No.4

No.40 - No.10 No.200 - No.40

0.002 mm - No.200 <0.002 mm

Auger Sample

Cement Grout

Filter Sand

Bentonite

Screen in filter sand

RX (Bedrock)

Slough

SPT

(1.375 I.D.)

Shelby Tube

No Recovery

FIGURESoil Boring Key

California Modified (2.5-inch I.D.)

California (2.0-inch I.D.)

GRAVEL AND

GRAVELLY

SOIL

B-1

* T _ *

PLASTICITY CHART

0 10

A LINE

=0.73(LL-20)

20 30 40 50 60 70 80 90 100

LIQUID LIMIT (LL) (%)

P

LA

S T

IC

IT

Y I

N D

E X

CL

CH

ML & OL

MH & OH

CL-ML

EMPIRICAL CORRELATIONS WITH STANDARD PENETRATION RESISTANCE N VALUES*

N Value *

(Blows/ft) Consistency Relative Density

<0.25

0.25 - 0.50

0.50 - 1.00

1.00 - 2.00

2.00 - 4.00

>4.00

0 - 2 3 - 4 5 - 8 9 - 15 16 - 30

>30

Very Soft Soft

Medium Stiff Stiff

Very Stiff Hard

0 - 4 5 - 10 11 - 30 31 - 50

>50

Very Loose Loose

Medium Dense Dense

Very Dense

*ASTM D 1586; number of blows of 140 pound hammer falling 30 inches to drive a 2-inch-O.D., 1.4-inch-I.D. sampler one foot.

Unconfined Compressive Strength (tons/sq ft)

N Value * (Blows/ft)

COARSE

GRAINED

SOIL

FINE

GRAINED

SOIL

S O

IL

K

E Y

S

F V

A M

C .G

P J

/8

/1

Concrete Brown SAND (SP), fine-grained, medium dense, moist becomes dense becomes medium dense

Brown clayey SAND (SC), fine-to coarse-grained, medium dense, low plasticity, moist.

1-1A 1-1

1-2A 1-2

1-3A 1-3

1-4A 1-4

1-5A 1-5

1-6

1-7A 1-7

MC

MC

MC

MC

MC

SPT

MC

SP

SC

Borehole Backfill: spoils, concrete

Finish Date: 8/14/15

Drilling Contractor: Taber Drilling

Hammer Type: Automatic Trip

Reviewed By: C. Trumbull

Start Date: 8/14/15

Logged By: Kyle Jermstad

Drilling Method: 8-inch Hollow Stem Auger

Remarks:

Total Depth Drilled (ft bgs): 40.0

Hammer Weight / Drop: 140 / 30

Arbitrary Ground Surface Elevation: 328.30

Drill Rig: CME-55

Groundwater Depth (ft): 30.5 ATD

Sheet 1 of 2

Log of Boring B-1

D ep th ft)

MATERIAL

DESCRIPTION

* T _ *LO

G

O F

B O

R

IN

G

S F

V A

M C

.G P

J

1/ 5/

SFVAMC - PICU Expansion & Renovation San Francisco, CA

Project Number: 11109034

E le va tio n (f t)

G ra ph ic

L og

B lo w s/

6"

S am pl e

T yp e

U nc or re ct ed

N V al ue

S am pl e/

R un

N o.

P oc ke t P en (t sf

U S

C S

C la ss ifi ca tio n

Li qu id L im it

P as si ng N o.

S ie ve

W at er C on te nt

D ry

D en si ty pc f)

T or va ne

(t sf

P la st ic ity In de x

A T

D

Brown clayey SAND (SC), fine-to coarse-grained, medium dense, low plasticity, moist.

with gravel, 3/8" diameter, rounded, very dense, wet.

Auger hit isolated rock

Becomes gray

Rig chatter, slow auger advancement Shale (Franciscan Formation), extremely to very weak, completely to highly weathered, gray.

Boring terminated at 41.5ft bgs. Groundwater encountered at 30.5ft bgs.

1-8A 1-8

1-9A 1-9

1-10

1-11

MC

MC

SPT

SPT

4.0

3.5

4.5+

4.5+

SC

RX

2.5

5.5

3.0

Sheet 2 of 2

Log of Boring B-1

D ep th ft)

MATERIAL

DESCRIPTION

* T _ *LO

G

O F

B O

R

IN

G

S F

V A

M C

.G P

J

1/ 5/

SFVAMC - PICU Expansion & Renovation San Francisco, CA

Project Number: 11109034

E le va tio n (f t)

G ra ph ic

L og

B lo w s/

6"

S am pl e

T yp e

U nc or re ct ed

N V al ue

S am pl e/

R un

N o.

P oc ke t P en (t sf

U S

C S

C la ss ifi ca tio n

Li qu id L im it

P as si ng N o.

S ie ve

W at er C on te nt

D ry

D en si ty pc f)

T or va ne

(t sf

P la st ic ity In de x

May 2011 Project No. 04.71110017

LEGEND

Approximate Location of Boring by Fugro (2011)

Approximate Location of Previous Borings near the proposed improvements by Others.

PLATE 2

SITE PLAN

SFVAMC - Welcome Center

San Francisco, California

Approx. Location of Proposed Welcome

Center

B-1

B-1

W 1-71 0 60 120

Scale: Approx. 1 in. = 60 ft.

B-2

B-3

SOURCE: This base map was provided by the Department of Veterans Affairs, dated September 18, 2001.

B-4

W 1-71 W F-62

W 8-71

W C-62 W D-62

W G-62

W 3-71

W 7-71

Approx. Location of Proposed Bus Turn

Around

Proposed Courtyard AreaProposed Courtyard

Area

Childs Mascari Warner Architects May 12, 2011 (Project No. 04.71110017)

G:\JOBDOCS\04.71110017 SFVA WELCOME CENTER\FINAL DOCS\REPORT-MAY11_SFVA.DOC

APPENDIX A

FIELD EXPLORATIONS

The field exploration program consisted of a surface reconnaissance and a subsurface exploration program. As a part of the geotechnical exploration for the project, four exploratory borings, designated B-01 through B-04, were conducted on April 12, 2011 to a maximum depth of about 51.5 feet. The borings were drilled with a track-mounted drill rig equipped with hollow stem auger drilling equipment and automatic hammer.

Representative soil samples were obtained from the boring using a Modified California split-barrel drive sampler (outside diameter of 3.0 inches, inside diameter of 2.5 inches) with liners, and a Standard Penetration Test (SPT) split-barrel drive sampler (outside diameter of 2.0 inches, inside diameter of 1.375 inches). All samples were transmitted to our laboratory for evaluation and appropriate testing. The sampler types are indicated in the "Sampler" column of the boring log as designated in Plate A-1.

Resistance blow counts were obtained with the samplers by dropping a 140-pound hammer through a 30-inch free fall using a wire-line safety hammer. The sampler was driven 18 inches, or a shorter distance where hard resistance was encountered, and the number of blows were recorded for each 6 inches of penetration. The blows per foot recorded on the boring logs represent the accumulated number of blows that were required to drive the last 12 inches. Due to the large diameter of the Modified California sampler, the blow counts for this sampler are not standard penetration resistance values. In order to convert these values to approximate standard penetration resistance values, the indicated blow counts should be multiplied by a factor of about 0.6.

Upon completion of our field explorations, the borings were backfilled with neat cement grout. The logs of the borings, as well as a key for the classification of the soil (Plate A-1) and Terms and Definitions Used for Rock (Plate A-2), are included as part of this appendix. The boring logs and related information show our interpretation of the subsurface conditions at the dates and locations indicated, and it is not warranted that they are representative of subsurface conditions at other locations and times.

The approximate locations of the exploratory borings are shown on the Site Plan, Plate 2.

GM

Fat CLAY

Elastic SILT

ORGANIC SILT

Lean CLAY

SILT

CLAYEY SAND

SILTY SAND

Poorly Graded SAND

Well-Graded SAND

Debris or Mixed Fill

A value of undrained shear strength is reported. The value is followed by a letter code indicating the type of test that was performed, as follows:

U - Unconfined Compression Q - Unconsolidated Undrained Triaxial T - Torvane P - Pocket Penetrometer M - Miniature Vane F - Field Vane R - R-value

50/3"

FI

N

E -G

R A

IN

E

D S

O

IL

S

GRAVELS

C O

A R

S E

-G R

A

IN

E D

S O

IL

S

M or e th an

0% re ta in ed on th e

N o.

s ie ve

SANDS

BLOW COUNT

N-VALUE

APPARENT DENSITY OF

COHESIONLESS SOIL

CONSISTENCY OF

COHESIVE SOIL

UNDRAINED SHEAR STRENGTH

OTHER TESTS

CLAYEY GRAVEL

0.25 to 0.50

SFVAMC

Project No. 04.71110017

SW

CH

OL

PT

SM

SP

Stiff

ORGANIC CLAY

1.0 to 2.0

UNDRAINED SHEAR STRENGTH

(KIPS PER SQUARE FOOT)

Note: In absence of test data, consistency has been estimated based on manual observation.

Medium Stiff

Very Soft

"WOH" indicates that the weight of the hammer was sufficient to advance the sampler over the first two intervals. 5 blows were required to advance the sampler over the third interval.

CL

MORE THAN 50% OF

COARSE FRACTION

RETAINED ON NO. 4

SIEVE

5, 7, and 8 blows for first, second, and third interval, respectively.

Collected from Auger

Other See log for details

Osterberg (Piston)

2-7/8" ID

Note: Refer to text of report for additional details or other sampler types.

Vibracore (Vibrated) See log for size

Pitcher Barrel (Rotary-cut)

2-7/8" ID

101 Geobarrel (Rotary-cut)

2-7/8" ID

Liquid Limit Greater than 50%

Liquid Limit Less than 50%

Shelby Tube (Pushed)

2-7/8" ID

3" OD

Modified California (Driven)

1-7/8" ID

2-1/2" OD

Modified California (Driven)

2-3/8" ID

3" OD

SPT

(Driven)

1-3/8" ID

2" OD

Number of blows required to drive sampler each of three 6-in. intervals, as measured in the field (uncorrected). An SPT hammer ( 140 lb., falling 30-in.) was used unless otherwise noted on the boring log. For example:

Peat or Highly Organic Soils

Seepage encountered

Initial water level Dry Moist Wet

INCREASING MOISTURE

CONTENT

WATER LEVEL SYMBOLS

Description

Push-core (Pushed) See log for size

Blow Count

CLASSIFICATION AND MATERIAL SYMBOLS

Poorly Graded

GRAVEL

GW

HIGHLY ORGANIC SOILS

SILTS AND CLAYS

SILTS AND CLAYS

A-1

WOH

WOH

SILTY GRAVEL

CONSISTENCY

Dense

> 4.0

2.0 to 4.0

0.50 to 1.0

APPARENT

DENSITY

Medium Dense

N-VALUE

Very Dense

Final water level

Well-Graded GRAVEL

> 49 30 to 49 10 to 29 5 to 9

Notes:

Classification of soils on the boring logs is in general accordance with ASTM D2488, or D2487 if appropriate laboratory data are available.

The geologic formation is noted in bold font at the top of interpreted interval on the boring logs.

Field or laboratory tests without a dedicated column on the boring log are reported in the Other Tests column. A letter code is used to indicate the type of test. For certain tests, a value representing the test result is also provided. Typical letter codes are as follows. Additional codes may be used. Refer to the report text and the laboratory testing results for additional information.

k - Permeability (cm/s) Consol - Consolidation Gs - Specific Gravity MA - Particle Size Analysis EI - Expansion Index OVM - Organic Vapor Meter

0 to 4< 0.25

35 blows for the first interval. 50 blows for the first 3 inches of the second interval. Lack of third value implies that driving was stopped 3 inches into the second interval.

SC

GP

Loose

MH

ML

GC

MAJOR DIVISIONS

PER ASTM D2488-06

Clean sand less than 5% fines

Pavement with Aggregate Base

Gravels with more than 12% fines

Sands with more than 12% fines

Clean gravels less than 5% fines

OH

MAJOR GROUP NAMES

AND MATERIAL SYMBOLS

The N-Value represents the blowcount for the last 12 inches of the sample drive if three 6-inch intervals were driven. N-value presented is independant of impact energy. If 50 hammer blows were insufficient to drive through either the second or the third interval, the total number of blows and total length driven are reported (excluding the first interval). "ref" (refusal) indicates that 50 blows were insufficient to drive through the first 6-inch interval.

Parenthesis indicate that an approximate correction has been applied for non-SPT drive samplers. For example, a factor of 0.63 is commonly used to adjust blow counts obtained using a 3-inch outside diameter modified California sampler to correspond to Standard Peneteration Test.

Soft

MORE THAN 50% OF

COARSE FRACTION

PASSING NO. 4 SIEVE

OTHER MATERIAL SYMBOLS

SAMPLER TYPE

TERMS AND SYMBOLS USED ON BORING LOGS PLATE A-1

o r m or e pa ss es th e N o.

s ie ve

Hard Very Stiff

Very Loose

Rock Core (Rotary-cut) See log for size

DESCRIPTION CHARACTERISTICS

Discoloraton or oxidation is limited to surface of, or short distance from fractures; some feldspar crystals are dull.

SFVAMC

Project No. 04.71110017

DESCRIPTION

Can be readily indented, grooved or gouged with fingernail, or carved with a pocketknife. Breaks with light manual pressure.

A-2

Decomposed

Slightly Weathered

Fresh

Moderately Weathered

Less than 1/4 inch.

Moderately Fractured

Unfractured

DESCRIPTION

Very Intensely Fractured

Very Slightly Fractured

CRITERIA

Cannot be scratched with a pocket knife or sharp pick. Breaks with repeated heavy hammer blows.

Soft

Moderately Soft

Moderately Hard

Hard

DESCRIPTION

Can be scratched with a pocket knife or sharp pick with difficulty (heavy pressure). Breaks with heavy hammer blows.

3 to 10 feet.

Thinly Bedded

Moderately Bedded

Thickly Bedded

Intensely Fractured

Massive

THICKNESS/SPACING

PLATE A-2

No fractures.

Very Thickly Bedded

AVERAGE

CRYSTAL

DIAMETER

DESCRIPTION

MATERIAL SYMBOLS

3/16 to 3/8 inch

Core lengths mostly from 1 to 3 feet.

OBSERVED FRACTURE DENSITY

Slightly Fractured

HARDNESS

Fine-Grained

Intensely Weathered

Core lengths mostly 4 inches to 1 foot.

Less than 1/250 inch

1/250 to 1/32 inch

1/32 to 3/16 inch

Greater of equal to 3/8 inch

Very Coarse Grained or Pegmatic

FRACTURE DENSITY

BEDDING SPACING

WEATHERING OF INTACT ROCK

Aphanitic

No discoloration, not oxidized.

Medium-Grained

Coarse-Grained

Mostly chips and fragments.

Core lengths mostly from 1 to 4 inches.

GRAIN SIZE FOR

CRYSTALLINE IGNEOUS

AND METAMORPHIC ROCK

Very Soft

Note: Composite or additional symbols may be shown on boring log. Refer to material description on boring log.

1 to 3 feet.

Greater than 10 feet.

TERMS AND SYMBOLS USED FOR ROCK

Siltstone

Sandstone

1 to 4 inches.

Cannot be scratched with a pocket knife or sharp pick. Can only be chipped with repeated heavy hammer blows.

1/4 to 1 inch.

Very Hard

Extremely Hard

Laminated

Very Thinly Bedded

Can be scratched with a pocket knife or sharp pick with light or moderate pressure. Core breaks with moderate hammer blows.

Other (refer to boring log)

4 inches to 1 foot.

Discoloration or oxidation extends from fractures usually throughout; Fe-Mg minerals are "rusty", feldspar crystals are "clowdy".

Bolders and Cobbles Discolored or oxidized throughout, but resistant minerals such as quartz may be unaltered; all feldspars and Fe-Mg minerals are completely altered to clay.

Discoloration or oxidation throughout; all feldspars and Fe-Mg minerals are altered to clay to some extent; or chemical alteration produces in situ disaggregation, see grain boundary conditions.

Basalt

Claystone

Core lengths greater than 3 feet.

Can be grooved or gouged easily with a pocket knife or sharp pick with light pressure. Can be scratched with fingernail. Breaks with light to moderate manual pressure.

Can be grooved 1/6-inch deep with a pocket knife or sharp pick with moderate or heavy pressure.

Breaks with light hammer blow or heavy manual pressure.

42"

18"

18"

18"

18"

18"

18"

18"

18"

18"

18"

18"

4.5" ASPHALT CONCRETE (AC)

10" AGGREGATE BASE (AB)

Poorly-graded SAND with SILT (SP-SM): brown, moist, fine to medium, subrounded to subangular fine to coarse gravel

- medium dense

- little to no gravel

Poorly-graded SAND (SP): loose to medium dense, brown, moist, fine to medium grained, trace silt

SILTY SAND (SM): loose, dark brown, moist, fine grained

- seepage at 21 ft

CLAYEY SAND (SC): loose to medium dense, dark brown mottled strong brown, moist, lenses of SANDY CLAY (CL)

- olive brown mottled strong brown

Lean CLAY (CL): stiff, dark greenish gray, moist, medium plasticity, appears to be decomposed bedrock

FRANCISCAN FORMATION (SHALE AND SHEARED ROCK):

decomposed, very soft, dark greenish gray, claylike

1.3 P

3.5 P

3.3 Q

BORING DEPTH: 45.4 ft BACKFILL: Grout DEPTH TO WATER: Seepage at 21' FIELDWORK DATE: April 12, 2011 DRILLING METHOD: 8-in. dia. Hollow Stem Auger

HAMMER TYPE: Automatic Trip

RIG TYPE: CME 55

DRIL…